Molybdenum(0) precursors for deposition of molybdenum films

ABSTRACT

Molybdenum(0) and coordination complexes are described. Methods for depositing molybdenum-containing films on a substrate are described. The substrate is exposed to a molybdenum precursor and a reactant to form the molybdenum-containing film (e.g., elemental molybdenum, molybdenum oxide, molybdenum carbide, molybdenum silicide, molybdenum disulfide, molybdenum nitride). The exposures can be sequential or simultaneous.

TECHNICAL FIELD

Embodiments of the disclosure relate to molybdenum precursors andmethods for depositing molybdenum-containing films. More particularly,embodiments of the disclosure are directed to molybdenum(0) complexescontaining 2n-electron donor neutral mono-, bi-, and tri-dentate ligandsand methods of use thereof.

BACKGROUND

The semiconductor processing industry continues to strive for largerproduction yields while increasing the uniformity of layers deposited onsubstrates having larger surface areas. These same factors incombination with new materials also provide higher integration ofcircuits per unit area of the substrate. As circuit integrationincreases, the need for greater uniformity and process control regardinglayer thickness rises. As a result, various technologies have beendeveloped to deposit layers on substrates in a cost-effective manner,while maintaining control over the characteristics of the layer.

Chemical vapor deposition (CVD) is one of the most common depositionprocesses employed for depositing layers on a substrate. CVD is aflux-dependent deposition technique that requires precise control of thesubstrate temperature and the precursors introduced into the processingchamber in order to produce a desired layer of uniform thickness. Theserequirements become more critical as substrate size increases, creatinga need for more complexity in chamber design and gas flow technique tomaintain adequate uniformity.

A variant of CVD that demonstrates excellent step coverage is cyclicaldeposition or atomic layer deposition (ALD). Cyclical deposition isbased upon atomic layer epitaxy (ALE) and employs chemisorptiontechniques to deliver precursor molecules on a substrate surface insequential cycles. The cycle exposes the substrate surface to a firstprecursor, a purge gas, a second precursor and the purge gas. The firstand second precursors react to form a product compound as a film on thesubstrate surface. The cycle is repeated to form the layer to a desiredthickness.

The advancing complexity of advanced microelectronic devices is placingstringent demands on currently used deposition techniques.Unfortunately, there is a limited number of viable chemical precursorsavailable that have the requisite properties of robust thermalstability, high reactivity, and vapor pressure suitable for film growthto occur. In addition, precursors that often meet these requirementsstill suffer from poor long-term stability and lead to thin films thatcontain elevated concentrations of contaminants such as oxygen,nitrogen, and/or halides that are often deleterious to the target filmapplication.

Molybdenum and molybdenum-based films have attractive material andconductive properties. These films have been proposed and tested forapplications from front end to back end parts of semiconductor andmicroelectronic devices. Processing a molybdenum precursor ofteninvolves use of halogen and carbonyl-based substituents. These ligandsprovide sufficient stability at the expense of reduced reactivity,increasing process temperature. There is, therefore, a need in the artfor molybdenum precursors that are free of halogen groups that react toform molybdenum metal and molybdenum-based films.

SUMMARY

One or more embodiments of the disclosure are directed to metalcoordination complexes. In one or more embodiments, a metal coordinationcomplex comprises molybdenum(0) and having a structure of Formula (I),Formula (II), or Formula (III):

wherein L is one or more of a 2n-electron donor neutral monodentateligand, 2n-electron donor neutral bidentate ligand, and a 2n-electrondonor neutral tridentate ligand, the metal coordination complexsubstantially free of halogen and substantially free of a Mo—O bond.

One or more embodiments of the disclosure are directed to a method ofdepositing a film. In one or more embodiments, a method of depositing afilm comprises: exposing a substrate to a molybdenum(0) precursor; andexposing the substrate to a reactant to form a molybdenum-containingfilm on a substrate surface, the molybdenum-containing filmsubstantially free of halogen.

Further embodiments of the disclosure are directed to methods ofdepositing a film. In one or more embodiments, a method of depositing afilm comprises: forming a molybdenum-containing film in a process cyclecomprising sequential exposure of a substrate to a molybdenum(0)precursor, purge gas, reactant, and purge gas.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the disclosurecan be understood in detail, a more particular description of thedisclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of the disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 illustrates a process flow diagram of a method in accordance withone or more embodiments of the disclosure.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the invention, it isto be understood that the invention is not limited to the details ofconstruction or process steps set forth in the following description.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways.

Embodiments of the disclosure provide precursors and processes fordepositing molybdenum-containing films. These metal coordinationcomplexes of one or more embodiments are substantially free of halogensand molybdenum oxygen bonds. The ligand may be 2n-electron donor neutralmono-, bi-, and tri-dentate ligands. The bonding between the ligandsprovides additional stability under ALD and CVD conditions. The processof various embodiments uses vapor deposition techniques, such as anatomic layer deposition (ALD) or chemical vapor deposition (CVD) toprovide molybdenum films. The molybdenum precursors of one or moreembodiments are volatile and thermally stable, and, thus, suitable forvapor deposition.

In one or more embodiments, the molybdenum precursor is free of halogen.In other embodiments, the molybdenum precursor is free of molybdenumoxygen (Mo—O) bonds. In one or more embodiments, the molybdenumprecursor if free of halogen and is free of molybdenum oxygen (Mo—O)bonds.

As used herein, the term “substantially free” means that there is lessthan less than about 5%, including less than about 4%, less than about3%, less than about 2%, less than about 1%, and less than about 0.5% ofhalogen, on an atomic basis, in the molybdenum-containing film. In someembodiments, the molybdenum-containing film is substantially free ofmolybdenum oxygen (Mo—O) bonds, and there is less than about 10%, lessthan about 9%, less than about 8%, less than about 7%, less than about6%, less than about 5%, including less than about 4%, less than about3%, less than about 2%, less than about 1%, and less than about 0.5% ofmolybdenum oxygen bonds, on an atomic basis, in themolybdenum-containing film.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metaloxides, metal nitrides, metal alloys, and other conductive materials,depending on the application. Substrates include, without limitation,semiconductor wafers. Substrates may be exposed to a pretreatmentprocess to polish, etch, reduce, oxidize, hydroxylate, anneal and/orbake the substrate surface. In addition to film processing directly onthe surface of the substrate itself, in the present invention, any ofthe film processing steps disclosed may also be performed on anunderlayer formed on the substrate as disclosed in more detail below,and the term “substrate surface” is intended to include such underlayeras the context indicates. Thus, for example, where a film/layer orpartial film/layer has been deposited onto a substrate surface, theexposed surface of the newly deposited film/layer becomes the substratesurface.

According to one or more embodiments, the method uses an atomic layerdeposition (ALD) process. In such embodiments, the substrate surface isexposed to the precursors (or reactive gases) sequentially orsubstantially sequentially. As used herein throughout the specification,“substantially sequentially” means that a majority of the duration of aprecursor exposure does not overlap with the exposure to a co-reagent,although there may be some overlap.

As used in this specification and the appended claims, the terms“precursor”, “reactant”, “reactive gas” and the like are usedinterchangeably to refer to any gaseous species that can react with thesubstrate surface.

“Atomic layer deposition” or “cyclical deposition” as used herein refersto the sequential exposure of two or more reactive compounds to deposita layer of material on a substrate surface. As used in thisspecification and the appended claims, the terms “reactive compound”,“reactive gas”, “reactive species”, “precursor”, “process gas” and thelike are used interchangeably to mean a substance with a species capableof reacting with the substrate surface or material on the substratesurface in a surface reaction (e.g., chemisorption, oxidation,reduction). The substrate, or portion of the substrate is exposedsequentially to the two or more reactive compounds which are introducedinto a reaction zone of a processing chamber. In a time-domain ALDprocess, exposure to each reactive compound is separated by a time delayto allow each compound to adhere and/or react on the substrate surface.In a spatial ALD process, different portions of the substrate surface,or material on the substrate surface, are exposed simultaneously to thetwo or more reactive compounds so that any given point on the substrateis substantially not exposed to more than one reactive compoundsimultaneously. As used in this specification and the appended claims,the term “substantially” used in this respect means, as will beunderstood by those skilled in the art, that there is the possibilitythat a small portion of the substrate may be exposed to multiplereactive gases simultaneously due to diffusion, and that thesimultaneous exposure is unintended.

In one aspect of a time-domain ALD process, a first reactive gas (i.e.,a first precursor or compound A) is pulsed into the reaction zonefollowed by a first time delay. Next, a second precursor or compound Bis pulsed into the reaction zone followed by a second delay. During eachtime delay a purge gas, such as argon, is introduced into the processingchamber to purge the reaction zone or otherwise remove any residualreactive compound or by-products from the reaction zone. Alternatively,the purge gas may flow continuously throughout the deposition process sothat only the purge gas flows during the time delay between pulses ofreactive compounds. The reactive compounds are alternatively pulseduntil a desired film or film thickness is formed on the substratesurface. In either scenario, the ALD process of pulsing compound A,purge gas, compound B and purge gas is a cycle. A cycle can start witheither compound A or compound B and continue the respective order of thecycle until achieving a film with the desired thickness. In someembodiments, there may be two reactants, A and B, that are alternatinglypulsed and purged. In other embodiments, there may be three or morereactants, A, B, and C, that are alternatingly pulsed and purged.

In an aspect of a spatial ALD process, a first reactive gas and secondreactive gas (e.g., hydrogen radicals) are delivered simultaneously tothe reaction zone but are separated by an inert gas curtain and/or avacuum curtain. The substrate is moved relative to the gas deliveryapparatus so that any given point on the substrate is exposed to thefirst reactive gas and the second reactive gas.

Without intending to be bound by theory, it is thought that the presenceof halogens in the structure of molybdenum (Mo) precursors can posechallenges, as halogen contamination may affect device performance andhence require additional removal procedures.

Molybdenum (Mo) can be grown by atomic layer deposition or chemicalvapor deposition for many applications. One or more embodiments of thedisclosure advantageously provide processes for atomic layer depositionor chemical vapor deposition to form molybdenum-containing films. Asused in this specification and the appended claims, the term“molybdenum-containing film” refers to a film that comprises molybdenumatoms and has greater than or equal to about 1 atomic % molybdenum,greater than or equal to about 2 atomic % molybdenum, greater than orequal to about 3 atomic % molybdenum, greater than or equal to about 4atomic % molybdenum, greater than or equal to about 5 atomic %molybdenum, greater than or equal to about 10 atomic % molybdenum,greater than or equal to about 15 atomic % molybdenum, greater than orequal to about 20 atomic % molybdenum, greater than or equal to about 25atomic % molybdenum, greater than or equal to about 30 atomic %molybdenum, greater than or equal to about 35 atomic % molybdenum,greater than or equal to about 40 atomic % molybdenum, greater than orequal to about 45 atomic % molybdenum, greater than or equal to about 50atomic % molybdenum, greater than or equal to about 60 atomic %molybdenum, greater than or equal to about 70 atomic % molybdenum,greater than or equal to about 80 atomic % molybdenum, greater than orequal to about 90 atomic % molybdenum, or greater than or equal to about95 atomic % molybdenum. In some embodiments, the molybdenum-containingfilm comprises one or more of molybdenum metal (elemental molybdenum),molybdenum oxide (MoO_(x)), molybdenum carbide (MoC_(x)), molybdenumsilicide (MoSi_(x)), molybdenum sulfide (MoS_(x)), or molybdenum nitride(MoN_(x)).

The skilled artisan will recognize that the use of molecular formulalike MoSi_(x) does not imply a specific stoichiometric relationshipbetween the elements but merely the identity of the major components ofthe film. For example, MoSi_(x) refers to a film whose major compositioncomprises molybdenum and silicon atoms. In some embodiments, the majorcomposition of the specified film (i.e., the sum of the atomic percentof the specified atoms) is greater than or equal to about 95%, 98%, 99%or 99.5% of the film, on an atomic basis.

With reference to FIG. 1, one or more embodiments of the disclosure aredirected to method 100 of depositing a film. The method illustrated inFIG. 1 is representative of an atomic layer deposition (ALD) process inwhich the substrate or substrate surface is exposed sequentially to thereactive gases in a manner that prevents or minimizes gas phasereactions of the reactive gases. In some embodiments, the methodcomprises a chemical vapor deposition (CVD) process in which thereactive gases are mixed in the processing chamber to allow gas phasereactions of the reactive gases and deposition of the thin film.

In some embodiments, the method 100 optionally includes a pre-treatmentoperation 105. The pre-treatment can be any suitable pre-treatment knownto the skilled artisan. Suitable pre-treatments include, but are notlimited to, pre-heating, cleaning, soaking, native oxide removal, ordeposition of an adhesion layer (e.g., titanium nitride (TiN)). In oneor more embodiments, an adhesion layer, such as titanium nitride, isdeposited at operation 105. In other embodiments, an adhesion layer isnot deposited.

At deposition 110, a process is performed to deposit amolybdenum-containing film on the substrate (or substrate surface). Thedeposition process can include one or more operations to form a film onthe substrate. In operation 112, the substrate (or substrate surface) isexposed to a molybdenum precursor to deposit a film on the substrate (orsubstrate surface). The molybdenum precursor can be any suitablemolybdenum-containing compound that can react with (i.e., adsorb orchemisorb onto) the substrate surface to leave a molybdenum-containingspecies on the substrate surface.

Current molybdenum precursors for ALD of metallic films use halogen andcarbonyl-based substituents, which provide sufficient stability at theexpense of reduced reactivity, increasing process temperature. Othermolybdenum precursors include anionic nitrogen ligands, which may leadto the formation of nitride impurities. Accordingly, one or moreembodiments use 2n-electron donor neutral mono-, bi-, and tri-dentateligand ligands to form thermally stable complexes. The hydrogen bondingbetween the ligands provides additional stability. This combinationgives provides molybdenum precursors having improved thermal stability,while retaining high volatility.

In one or more embodiments, the molybdenum precursor, specificallymolybdenum(0) precursors, has a structure of Formula (I), Formula (II),or Formula (III):

wherein L is one or more of a 2n-electron donor neutral monodentateligand, 2n-electron donor neutral bidentate ligand, and a 2n-electrondonor neutral tridentate ligand. In some embodiments, L is independentlyselected from the group consisting of alkene, amine, carbonyl,phosphine, and crown sulfur. The metal coordination complex may besubstantially free of halogen and substantially free of a Mo—O bond.

Unless otherwise indicated, the term “lower alkyl,” “alkyl,” or “alk” asused herein alone or as part of another group includes both straight andbranched chain hydrocarbons, containing 1 to 20 carbons, or 1 to 10carbon atoms, in the normal chain, such as methyl, ethyl, propyl,isopropyl, butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl,4,4-dimethylpentyl, octyl, 2,2,4-trimethyl-pentyl, nonyl, decyl,undecyl, dodecyl, the various branched chain isomers thereof, and thelike. Such groups may optionally include up to 1 to 4 substituents. Thealkyl may be substituted or unsubstituted.

In one or more embodiments, the metal coordination complex comprises astructure of Formula (I), Formula (II), or Formula (III). The structureof Formula (I), Formula (II), and Formula (III) may be selected from thegroup consisting of: Mo(CO)_(n)(PMe₃)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(CNMe)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(Py)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(SMe₂)_((6-n)) wherein n is from 1 to 3,

wherein n is from 1 to 3, and

wherein n is from 1 to 3.

As used herein, a “substrate surface” refers to any substrate surfaceupon which a layer may be formed. The substrate surface may have one ormore features formed therein, one or more layers formed thereon, andcombinations thereof. The substrate (or substrate surface) may bepretreated prior to the deposition of the molybdenum-containing layer,for example, by polishing, etching, reduction, oxidation, halogenation,hydroxylation, annealing, baking, or the like.

The substrate may be any substrate capable of having material depositedthereon, such as a silicon substrate, a III-V compound substrate, asilicon germanium (SiGe) substrate, an epi-substrate, asilicon-on-insulator (SOI) substrate, a display substrate such as aliquid crystal display (LCD), a plasma display, an electro luminescence(EL) lamp display, a solar array, solar panel, a light emitting diode(LED) substrate, a semiconductor wafer, or the like. In someembodiments, one or more additional layers may be disposed on thesubstrate such that the molybdenum-containing layer may be at leastpartially formed thereon. For example, in some embodiments, a layercomprising a metal, a nitride, an oxide, or the like, or combinationsthereof may be disposed on the substrate and may have the molybdenumcontaining layer formed upon such layer or layers.

At operation 114, the processing chamber is optionally purged to removeunreacted molybdenum precursor, reaction products and by-products. Asused in this manner, the term “processing chamber” also includesportions of a processing chamber adjacent the substrate surface withoutencompassing the complete interior volume of the processing chamber. Forexample, in a sector of a spatially separated processing chamber, theportion of the processing chamber adjacent the substrate surface ispurged of the molybdenum precursor by any suitable technique including,but not limited to, moving the substrate through a gas curtain to aportion or sector of the processing chamber that contains none orsubstantially none of the molybdenum precursor. In one or moreembodiments, purging the processing chamber comprises applying a vacuum.In some embodiments, purging the processing chamber comprises flowing apurge gas over the substrate. In some embodiments, the portion of theprocessing chamber refers to a micro-volume or small volume processstation within a processing chamber. The term “adjacent” referring tothe substrate surface means the physical space next to the surface ofthe substrate which can provide sufficient space for a surface reaction(e.g., precursor adsorption) to occur. In one or more embodiments, thepurge gas is selected from one or more of nitrogen (N₂), helium (He),and argon (Ar).

At operation 116, the substrate (or substrate surface) is exposed to areactant to form one or more of a molybdenum film on the substrate. Thereactant can react with the molybdenum-containing species on thesubstrate surface to form the molybdenum-containing film. In someembodiments, the reactant comprises a reducing agent. In one or moreembodiments, the reducing agent can comprise any reducing agent known toone of skill in the art. In other embodiments, the reactant comprises anoxidizing agent. In one or more embodiments, the oxidizing agent cancomprise any oxidizing agent known to one of skill in the art. Infurther embodiments, the reactant comprises one or more of oxidizingagent and a reducing agent.

In specific embodiments, the reactant is selected from one or more of1,1-dimethylhydrazine (DMH), alkyl amine, hydrazine, alkyl hydrazine,allyl hydrazine, hydrogen (H₂), ammonia (NH₃), alcohols, water (H₂O),oxygen (O₂), ozone (O₃), nitrous oxide (N₂O), nitrogen dioxide (NO₂),peroxides, N-oxides (e.g., Me₃NO, TEMPO), P-oxide (e.g., Et₃PO),S-oxides, and plasmas thereof. In some embodiments, the alkyl amine isselected from one or more of tert-butyl amine (tBuNH₂), isopropyl amine(iPrNH₂), ethylamine (CH₃CH₂NH₂), diethylamine ((CH₃CH₂)₂NH), or butylamine (BuNH₂). In some embodiments, the reactant comprises one or moreof compounds with the formula R′NH₂, R′₂NH, R′₃N, R′₂SiNH₂, (R′₃Si)₂NH,(R′₃Si)₃N; where each R′ is independently H or an alkyl group having1-12 carbon atoms. In some embodiments, the alkyl amine consistsessentially of one or more of tert-butyl amine (tBuNH₂), isopropyl amine(iPrNH₂), ethylamine (CH₃CH₂NH₂), diethylamine ((CH₃CH₂)₂NH), butylamine (BuNH₂).

At operation 118, the processing chamber is optionally purged afterexposure to the reactant. Purging the processing chamber in operation118 can be the same process or different process than the purge inoperation 114. Purging the processing chamber, portion of the processingchamber, area adjacent the substrate surface, etc., removes unreactedreactant, reaction products and by-products from the area adjacent thesubstrate surface.

At decision 120, the thickness of the deposited film, or number ofcycles of molybdenum-precursor and reactant is considered. If thedeposited film has reached a predetermined thickness or a predeterminednumber of process cycles have been performed, the method 100 moves to anoptional post-processing operation 130. If the thickness of thedeposited film or the number of process cycles has not reached thepredetermined threshold, the method 100 returns to operation 110 toexpose the substrate surface to the molybdenum precursor again inoperation 112 and continuing.

The optional post-processing operation 130 can be, for example, aprocess to modify film properties (e.g., annealing) or a further filmdeposition process (e.g., additional ALD or CVD processes) to growadditional films. In some embodiments, the optional post-processingoperation 130 can be a process that modifies a property of the depositedfilm. In some embodiments, the optional post-processing operation 130comprises annealing the as-deposited film. In some embodiments,annealing is done at temperatures in the range of about 300° C., 400°C., 500° C., 600° C., 700° C., 800° C., 900° C. or 1000° C. Theannealing environment of some embodiments comprises one or more of aninert gas (e.g., molecular nitrogen (N₂), argon (Ar)) or a reducing gas(e.g., molecular hydrogen (H₂) or ammonia (NH₃)) or an oxidant, such as,but not limited to, oxygen (O₂), ozone (O₃), or peroxides. Annealing canbe performed for any suitable length of time. In some embodiments, thefilm is annealed for a predetermined time in the range of about 15seconds to about 90 minutes, or in the range of about 1 minute to about60 minutes. In some embodiments, annealing the as-deposited filmincreases the density, decreases the resistivity and/or increases thepurity of the film.

The method 100 can be performed at any suitable temperature dependingon, for example, the molybdenum precursor, reactant, or thermal budgetof the device. In one or more embodiments, the use of high temperatureprocessing may be undesirable for temperature-sensitive substrates, suchas logic devices. In some embodiments, exposure to the molybdenumprecursor (operation 112) and the reactant (operation 116) occur at thesame temperature. In some embodiments, the substrate is maintained at atemperature in a range of about 20° C. to about 400° C., or about 50° C.to about 650° C.

In some embodiments, exposure to the molybdenum precursor (operation112) occurs at a different temperature than the exposure to the reactant(operation 116). In some embodiments, the substrate is maintained at afirst temperature in a range of about 20° C. to about 400° C., or about50° C. to about 650° C., for the exposure to the molybdenum precursor,and at a second temperature in the range of about 20° C. to about 400°C., or about 50° C. to about 650° C., for exposure the reactant.

In the embodiment illustrated in FIG. 1, at deposition operation 110 thesubstrate (or substrate surface) is exposed to the molybdenum precursorand the reactant sequentially. In another, un-illustrated, embodiment,the substrate (or substrate surface) is exposed to the molybdenumprecursor and the reactant simultaneously in a CVD reaction. In a CVDreaction, the substrate (or substrate surface) can be exposed to agaseous mixture of the molybdenum precursor and reactant to deposit amolybdenum-containing film having a predetermined thickness. In the CVDreaction, the molybdenum-containing film can be deposited in oneexposure to the mixed reactive gas or can be multiple exposures to themixed reactive gas with purges between.

In some embodiments, the molybdenum-containing film formed compriseselemental molybdenum. Stated differently, in some embodiments, themolybdenum-containing film comprises a metal film comprising molybdenum.In some embodiments, the metal film consists essentially of molybdenum.As used in this manner, the term “consists essentially of molybdenum”means that the molybdenum-containing film is greater than or equal toabout 80%, 85%, 90%, 95%, 98%, 99% or 99.5% A molybdenum, on an atomicbasis. Measurements of the composition of the molybdenum-containing filmrefer to the bulk portion of the film, excluding interface regions wherediffusion of elements from adjacent films may occur.

In other embodiments, the molybdenum-containing film comprisesmolybdenum oxide (MoO_(x)) with an oxygen content of greater than orequal to about 5%, 7.5%, 10%, 12.5% or 15%, on an atomic basis. In someembodiments, the molybdenum-containing film comprises an oxygen contentin the range of about 2% to about 30%, or in the range of about 3% toabout 25%, or in the range of about 4% to about 20%, on an atomic basis.

In other embodiments, the molybdenum-containing film comprisesmolybdenum carbide (MoC_(x)) with a carbon content of greater than orequal to about 5%, 7.5%, 10%, 12.5 or 15%, on an atomic basis. In someembodiments, the molybdenum-containing film comprises a carbon contentin the range of about 2% to about 30%, or in the range of about 3% toabout 25%, or in the range of about 4% to about 20%, on an atomic basis.

The deposition operation 110 can be repeated to form one or more of amolybdenum oxide film, a molybdenum carbide film, a molybdenum silicidefilm, a molybdenum disulfide film, and a molybdenum nitride film, havinga predetermined thickness. In some embodiments, the deposition operation110 is repeated to provide one or more of a molybdenum oxide film, amolybdenum carbide film, a molybdenum silicide film, and a molybdenumnitride film having a thickness in the range of about 0.3 nm to about100 nm, or in the range of about 30 Å to about 10 μM.

One or more embodiments of the disclosure are directed to methods ofdepositing molybdenum-containing films in high aspect ratio features. Ahigh aspect ratio feature is a trench, via or pillar having aheight:width ratio greater than or equal to about 10, 20, or 50, ormore. In some embodiments, the molybdenum-containing film is depositedconformally on the high aspect ratio feature. As used in this manner, aconformal film has a thickness near the top of the feature that is inthe range of about 80-120% of the thickness at the bottom of thefeature.

Some embodiments of the disclosure are directed to methods for bottom-upgapfill of a feature. A bottom-up gapfill process fills the feature fromthe bottom versus a conformal process which fills the feature from thebottom and sides. In some embodiments, the feature has a first materialat the bottom (e.g., a nitride) and a second material (e.g., an oxide)at the sidewalls. The molybdenum-containing film deposits selectively onthe first material relative to the second material so that themolybdenum film fills the feature in a bottom-up manner.

According to one or more embodiments, the substrate is subjected toprocessing prior to and/or after forming the layer. This processing canbe performed in the same chamber or in one or more separate processingchambers. In some embodiments, the substrate is moved from the firstchamber to a separate, second chamber for further processing. Thesubstrate can be moved directly from the first chamber to the separateprocessing chamber, or it can be moved from the first chamber to one ormore transfer chambers, and then moved to the separate processingchamber. Accordingly, the processing apparatus may comprise multiplechambers in communication with a transfer station. An apparatus of thissort may be referred to as a “cluster tool” or “clustered system,” andthe like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, degassing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura® and the Endura®, both available from AppliedMaterials, Inc., of Santa Clara, Calif. However, the exact arrangementand combination of chambers may be altered for purposes of performingspecific steps of a process as described herein. Other processingchambers which may be used include, but are not limited to, cyclicallayer deposition (CLD), atomic layer deposition (ALD), chemical vapordeposition (CVD), physical vapor deposition (PVD), etch, pre-clean,chemical clean, thermal treatment such as RTP, plasma nitridation,degas, orientation, hydroxylation, and other substrate processes. Bycarrying out processes in a chamber on a cluster tool, surfacecontamination of the substrate with atmospheric impurities can beavoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions and is not exposed to ambient airwhen being moved from one chamber to the next. The transfer chambers arethus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants (e.g., reactant). According to oneor more embodiments, a purge gas is injected at the exit of thedeposition chamber to prevent reactants (e.g., reactant) from movingfrom the deposition chamber to the transfer chamber and/or additionalprocessing chamber. Thus, the flow of inert gas forms a curtain at theexit of the chamber.

The substrate can be processed in single substrate deposition chambers,where a single substrate is loaded, processed, and unloaded beforeanother substrate is processed. The substrate can also be processed in acontinuous manner, similar to a conveyer system, in which multiplesubstrates are individually loaded into a first part of the chamber,move through the chamber, and are unloaded from a second part of thechamber. The shape of the chamber and associated conveyer system canform a straight path or curved path. Additionally, the processingchamber may be a carousel in which multiple substrates are moved about acentral axis and are exposed to deposition, etch, annealing, cleaning,etc. processes throughout the carousel path.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support, andflowing heated or cooled gases to the substrate surface. In someembodiments, the substrate support includes a heater/cooler which can becontrolled to change the substrate temperature conductively. In one ormore embodiments, the gases (either reactive gases or inert gases) beingemployed are heated or cooled to locally change the substratetemperature. In some embodiments, a heater/cooler is positioned withinthe chamber adjacent the substrate surface to convectively change thesubstrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated (about the substrate axis)continuously or in discrete steps. For example, a substrate may berotated throughout the entire process, or the substrate can be rotatedby a small amount between exposures to different reactive or purgegases. Rotating the substrate during processing (either continuously orin steps) may help produce a more uniform deposition or etch byminimizing the effect of, for example, local variability in gas flowgeometries.

The disclosure is now described with reference to the followingexamples. Before describing several exemplary embodiments of thedisclosure, it is to be understood that the disclosure is not limited tothe details of construction or process steps set forth in the followingdescription. The disclosure is capable of other embodiments and of beingpracticed or being carried out in various ways.

EXAMPLES Example 1: Preparation of Mo(CO)₃(PMe₃)₃

Mo(CO)₃(PMe₃)₃ was prepared by reacting Mo(CO)₆ with 3 equivalents oftrimethylphosphine in acetonitrile at 90° C. for 3 hours. The removal ofacetonitrile under vacuum provided the target precursor Mo(CO)₃(PMe₃)₃as a solid in 88% yield with a purity of 98%. Melting point 35° C.

¹H NMR (C₆D₆, 500 MHz, ppm): δ 0.76-0.74 (d, CH₃, J_(P-H)=10 Hz)

¹³C NMR (C₆D₆, 500 MHz, ppm): δ 206.0 (s, CO), 19.3 (s, CH3)

³¹P NMR (C₆D₆, 500 MHz, ppm): δ −16.9

Example 2: Preparation of Additional Molybdenum Precursors

Similar to Mo(CO)₃(PMe₃)₃, other precursors would be prepared byreacting Mo(CO)₆ with the corresponding ligands.

Example 3: Atomic Layer Deposition of Molybdenum Containing Films

General procedure: A silicon substrate was placed in a processingchamber. A molybdenum precursor was flowed into the processing chamberin an atmosphere of nitrogen (N₂) gas over the silicon substrate leavinga molybdenum-precursor terminated surface. Unreacted precursor andbyproducts were then purged out of the chamber. Next, a co-reactant wasthen introduced into the chamber that reacted with the surface-boundmolybdenum species. Again, excess coreactant and byproducts were removedfrom the chamber. The resultant material on the substrate was amolybdenum-containing film.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” may encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the materials and methods discussed herein(especially in the context of the following claims) are to be construedto cover both the singular and the plural, unless otherwise indicatedherein or clearly contradicted by context. Recitation of ranges ofvalues herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate the materials and methods and does not pose a limitation onthe scope unless otherwise claimed. No language in the specificationshould be construed as indicating any non-claimed element as essentialto the practice of the disclosed materials and methods.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure. In oneor more embodiments, the particular features, structures, materials, orcharacteristics are combined in any suitable manner.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

1. (canceled)
 2. (canceled)
 3. A metal coordination complex comprisingmolybdenum(0) and having a structure selected from the group consistingof: Mo(CO)_(n)(PMe₃)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(CNMe)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(Py)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(SMe₂)_((6-n)) wherein n is from 1 to 3,

and

wherein n is from 1 to 3, wherein the metal coordination complex issubstantially free of halogen and substantially free of a Mo—O bond. 4.A method of depositing a film, the method comprising: exposing asubstrate to a molybdenum(0) precursor; and exposing the substrate to areactant to form a molybdenum-containing film on a substrate surface,the molybdenum-containing film substantially free of halogen.
 5. Themethod of claim 4, wherein the molybdenum(0) precursor has a structureof Formula (I), Formula (II), or Formula (III):

wherein L is one or more of a 2n-electron donor neutral monodentateligand, 2n-electron donor neutral bidentate ligand, and a 2n-electrondonor neutral tridentate ligand.
 6. The method of claim 5, wherein L isindependently selected from the group consisting of alkene, amine,carbonyl, phosphine, and crown sulfur.
 7. The method of claim 5, whereinthe structure of Formula (I), Formula (II), and Formula (III)is selectedfrom the group consisting of: Mo(CO)_(n)(PMe₃)_((6-n)) wherein n is from1 to 3, Mo(CO)_(n)(CNMe)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(Py)_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(SMe₂)_((6-n)) wherein n is from 1 to 3,

wherein n is from 1 to 3, and

wherein n is from 1 to
 3. 8. The method of claim 4, wherein the reactantcomprises one or more of an oxidizing agent and a reducing agent.
 9. Themethod of claim 4, wherein the molybdenum-containing film comprises oneor more of a molybdenum metal (elemental Mo) film, a molybdenum oxidefilm, a molybdenum carbide film, a molybdenum silicide film, amolybdenum disulfide film, and a molybdenum nitride film.
 10. The methodof claim 4, wherein the substrate is exposed to the molybdenum(0)precursor and the reactant sequentially.
 11. The method of claim 4,wherein the substrate is exposed to the molybdenum(0) precursor and thereactant simultaneously.
 12. The method of claim 4, further comprisingpurging the substrate surface of the molybdenum(0) precursor prior toexposing the substrate to the reactant.
 13. The method of claim 12,wherein purging comprises one or more of applying a vacuum or flowing apurge gas over the substrate surface.
 14. The method of claim 13,wherein the purge gas comprises one or more of nitrogen (N₂), helium(He), and argon (Ar).
 15. A method of depositing a film, the methodcomprising: forming a molybdenum-containing film in a process cyclecomprising sequential exposure of a substrate to a molybdenum(0)precursor, purge gas, reactant, and purge gas.
 16. The method of claim15, wherein the molybdenum(0) precursor has a structure of Formula (I),Formula (II), or Formula (III):

wherein L is one or more of a 2n-electron donor neutral monodentateligand, 2n-electron donor neutral bidentate ligand, and a 2n-electrondonor neutral tridentate ligand.
 17. The method of claim 16, wherein Lis independently selected from the group consisting of alkene, amine,carbonyl, phosphine, and crown sulfur.
 18. The method of claim 16,wherein the structure of Formula (I), Formula (II), and Formula (III) isselected from the group consisting of: Mo(CO)_(n)(PMe₃)_((6-n)) whereinn is from 1 to 3, Mo(CO)_(n)(CNMe))_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(P_(y))_((6-n)) wherein n is from 1 to 3,Mo(CO)_(n)(SMe₂)_((6-n)) wherein n is from 1 to 3,

wherein n is from 1 to 3, and

wherein n is from 1 to
 3. 19. The method of claim 15, wherein purgingcomprises one or more of applying a vacuum or flowing a purge gas overthe substrate.
 20. The method of claim 19, wherein the purge gascomprises one or more of nitrogen (N₂), helium (He), and argon (Ar).